Name: heat transfer and specific heat
Uploaded: 2025-06-17T07:55:58.000Z
Duration: 2 min 46 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Chemistry

Energy

PS.Chm.7.2

Quantifying Heat

يتم تعريف الطاقة الداخلية من خلال التحويل البيني لكل من الحرارة والعمل. لكن كيف تقاس الحرارة؟كل مادة تمتلك طاقة حرارية. عندما يواجه النظام اختلافًا في درجة الحرارة مع محيطه،تتدفق الطاقة الحرارية من المادة ذات الحرارة المرتفعة،إلى المادة ذات الحرارة المنخفضة.هذا الانتقال للطاقة الحرارية يسمى النقل الحراري،ويقاس بالجول. درجة الحرارة،من ناحية أخرى،تصف خاصية الطاقة الحرارية،و تقاس بالدرجة المئوية أو بالكلفن. وبالتالي،فإن درجة الحرارة مستقلة عن المادة،على عكس الحرارة التي تعتمد على عدد ونوع الجزيئات في النظام.يمكن قياس الحرارة بتقنية تسمى مقياس-الكالوري،الذي يستخدم العلاقة بين الحرارة والتغير في درجة حرارة النظام. عندما تكون قطعة من الحديد عند 114 درجة مئوية ثم توضع في ماء بدرجة حرارة الغرفة،تتدفق الحرارة من الحديد إلى الماء حتى يصبح له نفس درجة حرارة الماء. بمجرد عدم وجود تدفق صافٍللحرارة،يكونوا في حالة توازن حراري.في نظام معزول،يكتسب الماء نفس مقدار الحرارة التي يخسرها الحديد. لكن درجة الحرارة النهائية،هي فقط،درجة واحدة أعلى من درجة حرارة الماء في البداية،بينما برد الحديد بمقدار 93 درجة مئوية. كمية الحرارة المنقولة تتناسب مع تغير درجة الحرارة دلتا T.ثابت التناسب C أو السعة الحرارية"هي كمية الحرارة اللازمة لرفع درجة حرارة النظام بمقدار واحد كلفن،أو درجة واحدة مئوية.تعتمد السعة الحرارية على نوع المواد:فنجد أنّالنظام ذو السعة الحرارية الكبيرة،مثل الماء،يحتاج لامتصاص قدر أكبر من الحرارة لرفع درجة حرارته من النظام ذو السعة الحرارية الأقل،مثل الحديد. تعتمد السعة الحرارية أيضا على كتلة المواد. تقوم السعة الحرارية الخاصة،Cs،أو السعة الحرارية الجزيئية،Cm،بوصف مقدار الحرارة المطلوبة لرفع درجة حرارة،1 غرام،أو 1 مول،من المادة بمقدار درجة واحدة مئوية.بالتالي،تعطى الوحدة،إما جول لكل غرام درجة مئوية،أو جول لكل مول درجة مئوية. إذا كان التغيير في السعة الحرارية الخاصة،و درجة الحرارة،معروفة في نظامٍما،فإنّقيمة الحرارة يمكن حسابها من نواتجهم.

قياس الحرارة

<h4>الطاقة الحرارية  </h4>بشكل ميكروسكوبي، الطاقة الحرارية هي الطاقة الحركية المرتبطة بالحركة العشوائية للذرات والجزيئات. إن درجة الحرارة مقياس كمي للحرارة “الساخنة” أو “الباردة”، وهو ما يعتمد على كمية الطاقة الحرارية. عندما تتحرك الذرات والجزيئات في جسم ما أو تهتز بسرعة، يكون متوسط الطاقة الحركية (KE) أعلى (أو طاقة حرارية أعلى)، ويُنظر إلى الجسم على أنه “ساخن”، أو يُوصف بأنه عند درجة حرارة أعلى. عندما تتحرك الذرات والجزيئات ببطء، يكون متوسط الطاقة الحركية KE عند مستوى أدنى (أو طاقة حرارية أقل)، ويُنظر إلى الجسم على أنه “بارد”، أو يُوصف بأنه عند درجة حرارة أقل.  بافتراض أنه لا يحدث أي تفاعل كيميائي أو تغير في الحالة (مثل الانصهار أو التبخر)، فإن زيادة كمية الطاقة الحرارية في عينة من المادة ستتسبب في زيادة درجة الحرارة، بينما يؤدي خفض كمية الطاقة الحرارية في عينة من المادة إلى انخفاض درجة الحرارة. <h4>الحرارة </h4>الحرارة (q) هي انتقال الطاقة الحرارية بين جسمين في درجات حرارة مختلفة. يزيد تدفق الحرارة من الطاقة الحرارية لأحد الأجسام ويقلل الطاقة الحرارية للآخر. تتدفق الحرارة تلقائياً من حرارة عالية إلى باردة (أي اتجاه واحد فقط) وتستمر حتى تصل درجة حرارة المادتين إلى درجة الحرارة نفسها. ويتم قياس التغيرات في الحرارة من خلال التغيرات في درجة الحرارة.  وحدة الحرارة والعمل والطاقة في النظام الدولي للوحدات هي الجول. يتم تعريف الجول (J) بأنه مقدار الطاقة المستخدمة عندما تتحرك قوة نيوتن (1 نيوتن) جسمًا طوله 1 متر. وقد سميت على شرف عالم الفيزياء الإنجليزي جيمس بريسكوت جول. يعادل جول واحد 1 كغ م2/s2، ويسمى أيضًا 1 نيوتن–متر. كيلو جول واحد (kJ) يساوي 1000 جول. ولتوحيد تعريفه، تم تعيين سعرة حرارية واحدة إلى 4.184 جول. <h4>نقل الطاقة الحرارية </h4>السعة الحرارية (C) لجسم المادة هي كمية الحرارة (q) التي تمتص أو تصدر عندما تشهد تغييرًا في درجة الحرارة (ΔT) بمقدار درجة مئوية واحدة (أو بشكل مكافئ، 1 كلفن): <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-01.png" style="height: 40px;" />يتم تحديد السعة الحرارية حسب نوع المادة التي تمتص الحرارة أو تطلق منها. لذلك، فإن السعة الحرارية هي خاصية واسعة النطاق — حيث تتناسب قيمتها مع كمية المادة. على سبيل المثال، ضع في اعتبارك السعة الحرارية لمقلاتين من الحديد المصبوب. تبلغ السعة الحرارية للمقلاة الكبيرة خمس أضعاف سعة المقلاة الصغيرة، لأنه على الرغم من أن المقلاتين مصنوعتان من نفس المادة، فإن كتلة المقلاة الكبيرة أكبر بخمس أضعاف من كتلة المقلاة الصغيرة. تعني الكتلة الأكبر وجود المزيد من الذرات في المقلاة الأكبر، لذا يتطلب الأمر مزيداً من الطاقة لجعل كل تلك الذرات تهتز بشكل أسرع. يمكن العثور على السعة الحرارية لمقلاة القلي الصغيرة من الحديد من خلال ملاحظة أنه يلزم زيادة مقدارها 18140 جول (q) لزيادة درجة حرارتها بمقدار 50.0 درجة مئوية° (&دلتا;T): <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-02.png" style="height: 40px;" />تتطلب المقلاة الكبيرة من الحديد الزهر، المصنوعة من نفس المادة، من الطاقة (q) 90700 J لرفع درجة حرارتها بمقدار 50.0 درجة مئوية (&دلتا;T). للمقلاة الأكبر سعة حرارية أكبر (نسبياً) لأن الكمية الأكبر من المادة تتطلب كمية أكبر من الطاقة (نسبياً) لإحداث نفس التغير في درجة الحرارة: <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-03.png" style="height: 40px;" />إن السعة الحرارية المحددة (c) للمادة، والتي يطلق عليها عادة “الحرارة النوعية,”، هي كمية الحرارة المطلوبة لرفع درجة حرارة غرام واحد من المادة بمقدار درجة مئوية واحدة (أو 1 كلفن):  <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-04.png" style="height: 40px;" />تعتمد السعة الحرارية المحددة فقط على نوع المادة التي تمتص الحرارة أو تطلق منها. إنها ملكية— مكثفة، لذا فهي غير معتمدة على كمية المادة. على سبيل المثال، مقلاة صغيرة من الحديد تحتوي على كتلة من 808 غ. ولذلك فإن الحرارة النوعية للحديد (المادة المستخدمة في صنع المقلاة) هي: 
 <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-05.png" style="height: 40px;" />تبلغ كتلة مقلاة القلي الكبيرة 4040 غ. باستخدام البيانات الخاصة بهذه الصَينية، يمكننا أيضًا حساب الحرارة النوعية للحديد:  <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-06.png" style="height: 40px;" />على الرغم من أن المقلاة الكبيرة أكبر من المقلاة الصغيرة، حيث أن المقلاة مصنوعة من نفس المادة، إلا أن كلاً منهما ينتج نفس القيمة بالنسبة لحرارة معينة (بالنسبة لمواد البناء، الحديد). لاحظ أن الحرارة النوعية تُقاس بوحدات الطاقة لكل درجة حرارة لكل كتلة وهي خاصية مكثفة، يتم اشتقاقها من نسبة خواصين شاملين (الحرارة والكتلة). إن الطاقة الحرارية المولية، وهي أيضاً خاصية مكثفة، هي السعة الحرارية لكل مول من مادة معينة، وهي تحتوي على وحدات من J/مول⋅°C.الماء له حرارة عالية نسبيا محددة (حوالي 4.2 J/g⋅°C للسائل و2.09 J/g⋅°C للصلب) ؛ معظم المعادن لديها درجات حرارة أقل بكثير (عادة أقل من 1 J/g⋅°C). من خلال معرفة كتلة مادة وحرارة معينة لها (m)، يمكن تحديد مقدار الحرارة، q، إدخال المادة أو مغادرتها عن طريق قياس تغير درجة الحرارة (ΔT) قبل وبعد اكتساب الحرارة أو فقدانها:  <img alt="Eq7" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-07v3.png" style="height: 20px;" /><img alt="Eq8" src="https://www.jovecore.com/CDNSource/lessons/794/794_Equations-08v4.png" style="height: 20px;" />إذا ارتفعت درجة حرارة المادة، وكانت درجة حرارتها النهائية أعلى من درجة حرارتها الأولية، Tنهائي − Tأولي فإن لها قيمة موجبة وقيمة q موجبة. إذا فقدت المادة الطاقة الحرارية، تنخفض درجة حرارتها، وتكون درجة الحرارة النهائية أقل من درجة الحرارة الأولية،Tنهائي − Tأولي فإن لها قيمة سالبة، وتكون قيمة q سالبة. لاحظ أنه يمكن استخدام العلاقة بين الحرارة والحرارة والكتلة وتغيير درجة الحرارة لتحديد أي من هذه الكميات (وليس الحرارة فقط) إذا كانت الكميات الثلاثة الأخرى معروفة أو يمكن استنتاجها. هذا النص مقتبس من <a href="https://openstax.org/books/chemistry-2e/pages/5-1-energy-basics">OpenStax Chemistry 2e, Section 5.1: Energy Basics</a> and <a href="https://openstax.org/books/chemistry-2e/pages/5-3-enthalpy">OpenStax Chemistry 2e, Section 5.3: Enthalpy</a>.

الطاقة الحرارية

من الناحية المجهرية ، الطاقة الحرارية هي الطاقة الحركية المرتبطة بالحركة العشوائية للذرات والجزيئات. درجة الحرارة هي ...

Education

JoVE Core

الكيمياء

واحد

Thermochemistry

الكيمياء الحرارية

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

heat transfer and specific heat

Heat transfer and specific heat explain how thermal energy moves and how materials respond to it. Thermal energy is the kinetic energy linked to the random motion of atoms and molecules. Temperature is a measure of how hot or cold a substance is, and it depends on how much thermal energy those particles have.

When atoms and molecules move or vibrate faster, their average kinetic energy is higher. That means the object has more thermal energy and a higher temperature. When they move more slowly, the thermal energy is lower and the temperature drops. If no chemical reaction or phase change, such as melting or vaporizing, occurs, adding thermal energy raises temperature and removing it lowers temperature.

Heat, written as q, is the transfer of thermal energy between two bodies at different temperatures. Heat flow increases the thermal energy of one body and decreases the thermal energy of the other. It moves spontaneously from hot to cold and continues until both substances reach the same temperature. Changes in heat are tracked by changes in temperature.

The SI unit for heat, work, and energy is the joule. One joule is the energy used when a force of 1 newton moves an object 1 meter. It is also equal to 1 kg m^2/s^2, or 1 newton-meter. A kilojoule is 1000 joules, and one calorie is defined as 4.184 joules.

Heat capacity, C, tells how much heat a body absorbs or releases when its temperature changes by 1 degree C, or 1 kelvin. It depends on both the type of substance and the amount present, so it is an extensive property. A large cast iron frying pan has a heat capacity five times greater than a small one because it has five times more mass. More mass means more atoms, so more energy is needed to make all of them vibrate faster.

The small cast iron frying pan in the example takes 18,140 J of energy to rise by 50.0 °C. The larger pan needs 90,700 J to rise by the same amount. Even though both pans are made of the same material, the larger one needs proportionally more energy because it contains more matter.

Specific heat capacity, often called specific heat, is the heat needed to raise 1 gram of a substance by 1 degree Celsius, or 1 kelvin. It depends only on the kind of substance, so it is an intensive property. Using the mass and temperature change of the small pan, the specific heat of iron can be calculated. The large pan gives the same result, even though its mass is greater.

Specific heat is measured in units of energy per temperature per mass. Because it is a ratio of heat and mass, it is intensive even though those two quantities are extensive. The molar heat capacity is another intensive property. It is the heat capacity per mole of a substance and has units of J/mol·°C.

Water has a relatively high specific heat, about 4.2 J/g·°C for liquid water and 2.09 J/g·°C for solid water. Most metals have much lower specific heats, usually less than 1 J/g·°C. If the mass of a substance, its specific heat, and its temperature change are known, the amount of heat entering or leaving it can be found. A positive q means thermal energy is gained and temperature rises. A negative q means thermal energy is lost and temperature falls.

Heat Transfer and Specific Heat

energy basics

How Energy Changes in Chemical Reactions

Chemical reactions change matter and energy at the same time. A match lighting is a simple example. These energy changes are part of everyday life and appear in food, fuels, and industry. Food provides energy through metabolic reactions. The macronutrients in food break down and help keep the body functioning. Fuels such as gasoline, natural gas, and coal are burned to produce energy for transportation, heating, and electricity generation. Industrial chemical reactions also use large amounts...

first law of thermodynamics

Energy Conservation and Internal Energy

Energy conservation describes how energy changes form during chemical and physical changes. Energy can be converted from one form into another, but the energy present before a change still exists in some form after the change is complete. This is the law of conservation of energy. It says energy can neither be created nor destroyed. The law of conservation of matter also applies during chemical change. In most chemical reactions, the total amount of matter does not show a detectable change.

internal energy

Internal Energy, Heat, and Work

Internal energy is the total of all possible kinds of energy in a substance. It is often written as U, and sometimes as E. For a system that changes energy, the important value is the change in internal energy, or ΔU. ΔU is the difference between the final internal energy and the initial internal energy. The exact values of U final and U initial are usually not known, but the first law of thermodynamics only requires ΔU. A positive ΔU means the system gained energy from the surroundings. A...

quantifying heat

Heat transfer and specific heat explain how thermal energy moves and how materials respond to it. Thermal energy is the kinetic energy linked to the random motion of atoms and molecules. Temperature is a measure of how hot or cold a substance is, and it depends on how much thermal energy those particles have. When atoms and molecules move or vibrate faster, their average kinetic energy is higher. That means the object has more thermal energy and a higher temperature. When they move more...

quantifying work

Pressure-Volume Work in Chemistry

Pressure-volume work shows how gas volume changes can transfer energy in chemistry. As a system changes, its internal energy may change too. Energy can move between the system and the surroundings through heat and work. Internal energy, heat, and work are related by an energy equation. Heat depends on a measured temperature change. Work depends on a measured change in volume called pressure-volume work. Work can be defined as a force acting through a distance. Pressure-volume work, also...

enthalpy

Enthalpy and Heat at Constant Pressure

Enthalpy describes heat changes in chemical and physical processes. Chemists use the symbol H for enthalpy. It is defined as a system’s internal energy, E, plus the product of pressure, P, and volume, V. Enthalpy is a state function, so only changes in enthalpy can be measured, not the enthalpy of a substance by itself. For many reactions, the pressure stays constant. Under those conditions, the enthalpy change, ΔH, can be written in a way that includes pressure-volume work. The term PΔV...

thermochemical equations

Heat Changes in Chemical Equations

Heat changes in chemical equations show how much energy a reaction releases or absorbs. At constant pressure, the enthalpy of reaction, or ΔHrxn, is equal to the heat exchanged with the surroundings, qp. Because this value depends on how much reactant takes part, it is an extensive property. The size and sign of ΔHrxn also depend on the reaction itself and on the physical states of the substances involved. An exothermic reaction has a negative ΔHrxn value, while an endothermic reaction has a...

constant pressure calorimetry

Coffee Cup Calorimeter Heat Changes

Coffee cup calorimetry measures heat changes in reactions and physical changes using an insulated calorimeter. The calorimeter is calibrated and designed to limit heat exchange with the outside environment. That makes it possible to measure the heat taken in or released by a substance more accurately, including the energy content of foods. In calorimetry, the system is the substance or substances undergoing change. The surroundings are everything else inside the calorimeter, including the...

constant volume calorimetry

Bomb Calorimeter Heat Measurement

Bomb calorimetry measures the heat released by reactions that produce a lot of energy, especially combustion reactions. A coffee cup calorimeter works at constant pressure and is useful for reactions in solution. A bomb calorimeter works at constant volume and is used for reactions that make large amounts of heat and gaseous products. The word "bomb" refers to the strong, explosive force some reactions can have. In a bomb calorimeter, the volume does not change, so 94V = 0. That means the...

hess's law

Calculating Reaction Heat with Hess's Law

Calculating reaction heat with Hess's law lets chemists find enthalpy changes without measuring every reaction directly. Some reactions are hard or impossible to test in the lab. Even when a reaction can be measured, it is often easier to calculate the heat change from other known enthalpy values. Hess's law says that if a process can be written as the sum of several stepwise processes, the enthalpy change for the total process equals the sum of the enthalpy changes for the steps. This works...

standard enthalpy of formation

Using Standard Enthalpy Values in Chemistry

Enthalpy changes are often listed for reactions that start and end under the same conditions. Chemists use a standard state as a reference set of conditions for comparing properties. In IUPAC terms, the standard state means 1 bar of pressure and 1 M solutions, but it does not set a temperature. Many thermochemical tables still use 1 atm as the reference pressure. Because the difference between 1 bar and 1 atm is very small, enthalpy change usually stays almost the same. A superscripted o in...

enthalpies of reaction

Calculating reaction heat with Hess's law uses standard enthalpies of formation to find the enthalpy change of a reaction. When the formation values for the reactants and products are known, the overall reaction can be broken into simpler stepwise reactions. This approach helps show how the heat change for the full reaction is built from smaller parts. First, the reactants are thought of as being decomposed into their component elements. The enthalpy change for this step is proportional to the...

key terms and concepts

Learn how heat moves between objects, why temperature changes, and how heat capacity and specific heat help measure thermal energy in materials.

Heat Transfer and Specific Heat | JoVE K12

chemistry

JoVE Core Chemistry brings general chemistry concepts to life using concise and easy-to-understand animated video lessons. Plus, in the scientist-in-action videos, we demonstrate classical and original research experiments performed in today's laboratories worldwide.

Matter and its Interactions

PS.Chm.4.1

Louisiana Student Standards for Science

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HS-PS3-3

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Ohio’s Learning Standards and Model Curriculum

Physical Science

Energy And Waves

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Transfer and transformation of energy (including work)

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Chemical reactions

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South Carolina College and Career Ready Science Standards

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New York State Science Learning Standards

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Georgia Standards of Excellence

SPS7.

Modes of Heat Transfer

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

comparing-intermolecular-forces-melting-point-boiling-point

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

surface-tension-capillary-action-and-viscosity

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded ...

States of Matter and Phase Changes

The internal energy of a substance&#8212;the total kinetic energy of all its molecules and the potential energy of their associated forces&#8212;depends ...

Phase Transitions

Whether solid, liquid, or gas, a substance&#39;s state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the ...

phase-transitions-vaporization-and-condensation

Phase Transitions: Vaporization and Condensation

The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize ...

Vapor Pressure

When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules move randomly about, they will occasionally ...

Clausius-Clapeyron Equation

The equilibrium between a liquid and its vapor depends on the temperature of the system; a rise in temperature causes a corresponding rise in the vapor ...

Phase Transitions: Melting and Freezing

Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy ...

phase-transitions-sublimation-and-deposition

Phase Transitions: Sublimation and Deposition

Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and ...

Heating and Cooling Curves

When a substance&#8212;isolated from its environment&#8212;is subjected to heat changes, corresponding changes in temperature and phase of the substance ...

Phase Diagrams

A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. ...

Use models to explain how changes in energy affect the arrangement and movement of the particles in solids, liquids, and gases, as well as the relative strengths of their intermolecular forces.

PS.Chm.7.1

Energy Basics

Chemical reactions, such as those that occur when you light a match, involve changes in energy as well as matter.

Chemical changes and their accompanying ...

First Law of Thermodynamics

Energy Conservation

Energy can be converted from one form into another, but all of the energy present before a change occurs always exists in some form ...

Internal Energy

The total of all possible kinds of energy present in a substance is called the internal energy (U), sometimes symbolized as E. Suppose a system with ...

Thermal Energy&#160;

Microscopically, thermal energy is the kinetic energy associated with the random motion of atoms and molecules. Temperature is a ...

Quantifying Work

As a system undergoes a change, its internal energy can change, and energy can be transferred from the system to the surroundings, or from the ...

Enthalpy

Chemists ordinarily use a property known as enthalpy (H) to describe the thermodynamics of chemical and physical processes. Enthalpy is defined as the sum ...

Thermochemical Equations

For a chemical reaction (the system) carried out at constant pressure &ndash; with the only work done caused by expansion or contraction &ndash; the ...

Constant Pressure Calorimetry

Calorimetry is a technique used to measure the amount of heat involved in a chemical or physical process or to measure the heat transferred to or from a ...

Constant Volume Calorimetry

Calorimeters are useful to determine the heat released or absorbed by a chemical reaction. Coffee cup calorimeters are designed to operate at constant ...

using-differential-scanning-calorimetry-to-measure-changes-in-enthalpy

Using Differential Scanning Calorimetry to Measure Changes in Enthalpy

Source: Laboratory of Dr. Terry Tritt &#8212; Clemson University
Differential Scanning Calorimetry (DSC) is a method of thermodynamic analysis based on ...

Hess's Law

There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally ...

Standard Enthalpy of Formation

Enthalpy changes are typically tabulated for reactions in which both the reactants and products are at the same conditions. A standard state is a commonly ...

Enthalpies of Reaction

Hess&rsquo;s law can be used to determine the enthalpy change of any reaction if the corresponding enthalpies of formation of the reactants and products ...

Use mathematics and computational thinking to execute simple calorimetric calculations based on the Law of Conservation of Energy.

definition-measurement-pressure-atmospheric-pressure-barometer

Definition and Measurement of Pressure: Atmospheric Pressure, Barometer, and Manometer

Gas pressure is caused by force exerted by gas molecules colliding with the surfaces of objects. Although the force of each collision is very small, any ...

gas-laws-boyle-s-gay-lussac-charles-avogadro-s-and-ideal-gas-law

Gas Laws: Boyle's, Gay-Lussac, Charles', Avogadro's, and Ideal Gas Law

Through experiments, scientists established the mathematical relationships between pairs of variables, such as pressure and temperature, pressure and ...

applications-of-the-ideal-gas-law-molar-mass-density-and-volume

Applications of the Ideal Gas Law: Molar Mass, Density, and Volume

The volume occupied by one mole of a substance is its molar volume. The ideal gas law, PV = nRT, &nbsp;suggests that the volume of a given quantity of gas ...

mixtures-of-gases-dalton-s-law-of-partial-pressures-and-mole-fractions

Mixtures of Gases: Dalton's Law of Partial Pressures and Mole Fractions

Unless individual gases chemically react with each other, the individual gases in a mixture of gases do not affect each other&rsquo;s pressure. Each gas ...

chemical-stoichiometry-gases-using-ideal-gas-law-to-determine

Chemical Stoichiometry and Gases: Using Ideal Gas Law to Determine Moles

Chemical stoichiometry describes the quantitative relationships between reactants and products in chemical reactions.

In addition to measuring quantities ...

basic-postulates-kinetic-molecular-theory-particle-size-energy

Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision

The ideal-gas equation, which is empirical, describes the behavior of gases by establishing relationships between their macroscopic properties. For ...

kinetic-molecular-theory-gas-laws-explain-properties-gas

Kinetic Molecular Theory and Gas Laws Explain Properties of Gas Molecules

The test of the kinetic molecular theory (KMT) and its postulates is its ability to explain and describe the behavior of a gas. The various gas laws ...

kinetic-molecular-theory-molecular-velocities-temperature-kinetic

Kinetic Molecular Theory: Molecular Velocities, Temperature, and Kinetic Energy

The kinetic molecular theory qualitatively explains the behaviors described by the various gas laws. The postulates of this theory may be applied in a ...

Use mathematics and computational thinking to explain the relationships among pressure, temperature, volume, and quantity of gas, both qualitatively and quantitatively.

PS.Chm.7.3

Understand the relationship among pressure, temperature, volume, and phase.

Heat Transfer and Specific Heat

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